Circuit Description
The system relay is energized when the ignition is ON. The system relay supplies voltage to the valve solenoids and the pump motor. This voltage is referred to as the system voltage. The electronic brake control module (EBCM) microprocessor activates the valve solenoids by grounding the control circuit.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC C1261 Left Front Inlet Solenoid Malfunction |
| • | DTC C1262 Left Front Outlet Solenoid Malfunction |
| • | DTC C1263 Right Front Inlet Valve Solenoid Malfunction |
| • | DTC C1264 Right Front Outlet Valve Solenoid Malfunction |
| • | DTC C1265 Left Rear Inlet Valve Solenoid Malfunction |
| • | DTC C1266 Left Rear Outlet Valve Solenoid Malfunction |
| • | DTC C1267 Right Rear Inlet Valve Solenoid Malfunction |
| • | DTC C1268 Right Rear Outlet Valve Solenoid Malfunction |
| • | DTC C1272 Left Front TCS Valve Solenoid Malfunction |
| • | DTC C1274 Right Front TCS Valve Solenoid Malfunction |
Conditions for Running the DTC
| • | The system voltage is greater than 8 volts. |
| • | The ignition voltage is greater than 9 volts. |
Conditions for Setting the DTC
The commanded state of the driver and the actual state of the control circuit do not match for 0.03 seconds.
Action Taken When the DTC Sets
If equipped, the following actions occur:
| • | The EBCM disables the ABS/TCS for the duration of the ignition cycle. |
| • | The DRP does not function optimally. |
| • | The ABS indicator turns ON. |
| • | The Traction Off indicator turns ON. |
| • | The message center displays the Service Traction System message. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and the DTC is cleared with a scan tool. |
| • | The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
Diagnostic Aids
The solenoid valve circuit is internal to the EBCM. The solenoid valve circuit is not diagnosable external to the EBCM. The DTC sets when there is a malfunction in the solenoid circuit internal to the EBCM.
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
Does the DTC reset as a current DTC? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | |
3 | Replace the electronic brake control module (EBCM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the repair? | Go to Step 4 | -- |
4 |
Does the DTC reset? | Go to Step 2 | System OK |
